1. Field of the Invention
The present invention relates to safety needle devices for safe and convenient handling of needles. More particularly, the present invention relates to a shieldable needle device having a forward moving safety shield for protection from a used needle tip.
2. Description of Related Art
Disposable medical devices having medical needles are used for administering medication or withdrawing fluid from the body of a patient. Such disposable medical devices typically include blood-collecting needles, fluid handling needles and assemblies thereof. Current medical practice requires that fluid containers and needle assemblies used in such devices be inexpensive and readily disposable. Consequently, existing blood collection devices typically employ some form of durable, reusable holder on which detachable and disposable medical needles and fluid collection tubes may be mounted. A blood collection device of this nature may be assembled prior to use and then disassembled after use. Thus, these blood collection devices allow repeated use of a relatively expensive holder upon replacement of relatively inexpensive medical needles and/or fluid collection tubes. In addition to reducing the cost of collecting blood specimens, these blood collection devices help minimize the production of hazardous waste material.
A blood collection device or intravenous (IV) infusion device typically includes a needle cannula having a proximal end, a pointed distal end, and a lumen extending therebetween. The proximal end of the needle cannula is securely mounted in a plastic hub defining a central passage that communicates with the lumen extending through the needle cannula. A thin, flexible thermoplastic tube is connected to the hub and communicates with the lumen of the needle cannula. The end of the plastic tube remote from the needle cannula may include a fixture for connecting the needle cannula to a blood collection tube or other receptacle. The specific construction of the fixture will depend upon the characteristics of the receptacle to which the fixture is to be connected.
In order to reduce the risk of incurring an accidental needle-stick wound, protection of used needle cannulas becomes important. With concern about infection and transmission of diseases, methods and devices to enclose or cover the used needle cannula have become very important and in great demand in the medical field. For example, needle assemblies commonly employ a safety shield that can be moved into shielding engagement with a used needle cannula to minimize risk of an accidental needle stick.
For example, U.S. Pat. No. 4,892,521 to Laico et al. discloses a telescoping protective cover, which utilizes a pair of guide members to extend a telescoping tip guard to a shielding position. The guide members are diametrically located and function to guide the tip guard to the protective position and may be spring biased.
U.S. Pat. No. 5,423,766 to DiCesare discloses a safety shield including a tip guard that is slideably movable along the needle from a proximal position to a distal position. The safety shield utilizes a spring tether which is connected to a guard and an anchor. The tether is deflected into a loop with the guard and anchor preventing the tether from springing open.
Such prior art devices are typically difficult to manufacture and require complex operation to operate. In view of the foregoing, a need exists for a blood collection set including a shieldable needle device that achieves secure and effective shielding of a used needle cannula, which is easy to manufacture and is simple and safe to operate.